1. Field
The present invention relates to coordinate measurement, and more particularly to mobile coordinate measurement machines.
2. Description of the Related Art
Rectilinear measuring systems, also referred to as coordinate measuring machines and articulated arm measuring machines, are used to generate highly accurate geometry information. In general, these instruments capture the structural characteristics of an object for use in quality control, electronic rendering and/or duplication. One example of a conventional apparatus used for coordinate data acquisition is a portable coordinate measuring machine (PCMM), which is a portable device capable of taking highly accurate measurements within a measuring sphere of the device. Such devices often include a probe mounted on an end of an arm that includes a plurality of transfer members connected together by joints. The end of the arm opposite the probe is typically coupled to a moveable base. Typically, the joints are broken down into singular rotational degrees of freedom, each of which is measured using a dedicated rotational transducer. During a measurement, the probe of the arm is moved manually by an operator to various points in the measurement sphere. At each point, the position of each of the joints must be determined at a given instant in time. Accordingly, each transducer outputs an electrical signal that varies according to the movement of the joint in that degree of freedom. Typically, the probe also generates a signal. These position signals and the probe signal are transferred through the arm to a recorder/analyzer. The position signals are then used to determine the position of the probe within the measurement sphere. See e.g., U.S. Pat. Nos. 5,829,148; 7,174,651; and 8,112,896, issued on 3 Nov. 1998, 13 Feb. 2007, and 14 Feb. 2012, respectively, which are incorporated herein by reference in their entireties.
Generally, these devices are mounted on a stable and rigid surface such as a table. In some instances, they may be rigidly attached to said surface by fasteners, suction devices, or the like. Such mounting techniques reduce the portability of the coordinate measurement machine. The disclosure herein provides improvements of at least some of these qualities.